The invention relates to an electrically actuated rotary drive device, with a gear casing having a front side, and a rear side opposite the former, and on which is rotatably mounted an output member accessible at the front side of the gear casing and in driving connection with a driven gear mounted rotatably in the gear casing and in gearing engagement with a drive pinion of an electrical drive motor mounted externally at the rear side of the gear casing.
A rotary drive device of this type known from DE 10 2011 107 012 A1 is equipped with a hybrid drive system and also contains, besides an electrical drive motor, a drive device actuatable by fluid power, wherein both the drive motor and also the fluidically actuatable drive device act on an output member accessible at a front side of a gear casing, in order to set this output member into rotary movement. The power flow between the drive motor attached to the rear side of the gear casing and the output member is obtained by means of a gear located inside the gear casing and having a driven gear in driving connection with the output member and a drive pinion drivable by the drive motor and in gearing engagement with the driven gear. Both the drive pinion and the driven gear have an external gear teeth system, so that they are mounted next to one another in a plane at right-angles to the rotation axis and the driven gear is flanked on the radial outside by the drive pinion.
In the case of the known rotary drive device, the electrical drive motor may be accommodated with relative ease, since its dimensions can be kept relatively small due to the presence of the additional drive device operated by fluid power. Problems occur, however, if the rotary drive device is to be operated purely electrically, since the drive motor then required has larger dimensions because of the increased power requirement, with adverse effects on the compactness of the rotary drive device.
Known from a publication of the Oriental Motor Europa GmbH dated 2011, pages 1 and 4, is an electrical rotary drive device in which, similarly, a driven gear provided with an external gear teeth system meshes with a drive pinion, wherein however the engagement zone between the two tooth systems, unlike in the case of DE 10 2011 107 012 A1, is not assigned to a corner zone of the gear casing, but instead lies between two corner zones of a mounting frame.